What is the best self-levelling compound in the UK? There is no single winner — match the compound to the floor. For most indoor floors before tile, LVT or laminate, Ark stocks Larsen SLC1550: single-part, fibre-reinforced, 3–50mm in one pour, light foot traffic in 2–4 hours, overlay in 1–3 days (product page / drying guide). Lively timber → LLC206 NA. Sound concrete/screed skim → SLC100 (pallet). Outdoors → SLC2500. Bag counts: levelling calculator. Dated bag and pallet prices: SLC1550 buying guide.
We supply levelling compound to installers from our Coventry trade counter. The tables below use only figures already on each Larsen product page or on our published drying / buying guides — not a league table of every brand.
This guide picks a compound by job. For SLC1550 bag and pallet prices, which primer and a worked bag count, use the SLC1550 buying guide. For cure and walk-on detail, see the SLC1550 drying guide.
How to choose (criteria)
Depth bands
Values from each live product page. Em dash means the product page does not state a figure — do not guess.
| Job depth | Typical use | Ark pick | Stated depth on PDP |
|---|---|---|---|
| 3–50mm in one pour | Most indoor floors before tile, LVT or laminate | Larsen SLC1550 | 3–50mm |
| Feather–10mm (to 30mm with aggregate) | Flexible latex over demanding / timber substrates | Larsen LLC206 NA | Feather edge to 10mm; up to 30mm with aggregate |
| Feather–6mm | Concrete and sand/cement screeds | Larsen SLC100 (48-bag pallet) | Feather to 6mm |
| — | Outdoor patios, balconies, external tiled areas | Larsen SLC2500 | — (not stated on PDP; external use only) |
Walk-on and overlay times
Follow the bag and the current Larsen datasheet for your depth and site conditions. Detail for SLC1550 is on our drying time & coverage guide.
| Product | Light foot traffic | Cover with floor finish | Source on Ark |
|---|---|---|---|
| SLC1550 | 2–4 hours | Overlay in 1–3 days | PDP + drying guide |
| LLC206 NA | 1–2 hours | Floorcoverings from 4–6 hours | PDP |
| SLC100 | Foot traffic in 4 hours | — | PDP |
| SLC2500 | — | — | Not stated on PDP |
How you mix it
We do not publish machine-application rates here — they are not on our live product pages. Use the mix type the bag is built for.
| Mix type | What you do on site | Ark pick |
|---|---|---|
| Single-part cementitious | Just add clean water, mix, and pour (hand / site mix as per bag) | SLC1550 (also SLC100 / SLC2500 are cementitious — follow each bag) |
| Two-part latex | Mix powder with the supplied liquid latex (LLC206: one 4.5L liquid per 20kg) | LLC206 NA |
Indoor use and substrate
| Setting | Substrate notes (from Ark pages) | Ark pick |
|---|---|---|
| Indoor — general | Before tile, LVT or laminate; UFH-compatible (SLC1550) | SLC1550 |
| Indoor — timber / lively boards | Two-part latex; rigid boards may still suit SLC1550 — see wooden floors guide | LLC206 NA (or SLC1550 on rigid boards) |
| Indoor — concrete / sand-cement screed skim | Feather to 6mm | SLC100 |
| Outdoor | External formulation; not a substitute for an indoor leveller outdoors | SLC2500 |
Best all-rounder: Larsen SLC1550 Rapid Set Pro
The one we sell more of than everything else combined. Single-part (just add water), fibre-reinforced, flexible, and pours 3–50mm in one application — so it handles everything from a 3mm skim to seriously uneven renovation floors. Walk on it in 2–4 hours, overlay in 1–3 days, use it over underfloor heating and rigid timber. A single 20kg bag is £13.19 (prices checked 6 Nov 2026). View SLC1550 →
Best for wooden floors: Larsen LLC206 NA
A protein-free, two-part latex compound — the specification-grade answer for floorboards, old timber and other demanding substrates where maximum flexibility matters. More on when to choose latex in our wooden floors guide. View LLC206 NA →
Best for smoothing concrete and sand/cement screeds: Larsen SLC100
For concrete and sand/cement screeds, feather to 6mm. The 48-bag pallet is £489.99 (prices checked 6 Nov 2026). View the SLC100 pallet →
Best for external use: Larsen SLC2500
Most levellers are interior-only. SLC2500 Professional External is the exception — formulated for outside use, ideal before laying porcelain paving on an uneven base. View SLC2500 →
Before you buy
Work out bags with our levelling compound calculator (planning rate: about 1 m² per 20kg bag at 10mm). For dated bag and pallet prices, primer and a worked example, use the SLC1550 buying guide. Shop self-levelling compound, compare SLC1550 pallet deals, or set up regular pallets via trade. Cure times: SLC1550 drying guide. Free UK delivery over £499.
FAQs
What is the best self-levelling compound for concrete floors?
For a general indoor pour before tile/LVT/laminate, start with SLC1550 (3–50mm). For a thin skim on sound concrete or sand/cement screed, see SLC100 (feather to 6mm, pallet). Use the depth and walk-on tables above — not a brand league table.
What is the best latex self-levelling compound?
At Ark that is Larsen LLC206 NA (two-part, protein-free). Light foot traffic 1–2 hours; floorcoverings from 4–6 hours on the product page. Timber detail: wooden floors guide.
How long before I can walk on self-levelling compound?
SLC1550: 2–4 hours light foot traffic; overlay 1–3 days. LLC206: 1–2 hours / floorcoverings 4–6 hours. Full SLC1550 detail on the drying guide.
How many bags do I need?
Use the calculator. Planning rate about 1 m² per bag at 10mm. The buying guide has the Larsen TDS 5mm example and live prices.
What is the best self-levelling compound for underfloor heating?
At Ark that is Larsen SLC1550. Its product page lists it as compatible with underfloor heating, 3–50mm in one pour. Prime with Larsen Acrylic Primer, which its product page lists for heated concrete and cement screeds up to a maximum surface temperature of 35°C. Keep the heating off while pouring and during the initial cure. More detail is in the drying guide.
What is the best exterior self-levelling compound?
Larsen SLC2500 is the external leveller we stock. Its product page says it is designed for external use, weather-, frost- and moisture-resistant, for patios, balconies and external tiled areas. It is sold as a 48 × 25kg pallet. The product page does not give a depth range or walk-on time, so follow the bag.
What is the best self-levelling compound over existing tiles?
At Ark that is Larsen SLC1550. The Larsen Professional SLC 1550 Flex technical data sheet (v03 Nov 2024) lists ceramic tiling as a suitable substrate when it is structurally sound, thoroughly clean and dry, and free from laitance, grease, oils, paint or other contaminants which may impair adhesion — suitable mechanical preparation may be required. Prime with Larsen Acrylic Primer as directed on the product page. This over-tiles claim applies to SLC1550 only, not to LLC206 NA, SLC100 or SLC2500.
0 comments